Endgame needs midcore content. In the middle thats harder than the normal duty content but is easier than EX. Ultima unreal (while being a former EX scaled up) was a good concept for a difficulty level of midcore content. Just a few simple mechs and a dps check that is easily doable even with multiple deaths, but is dangerous enough to still wipe you or hit enrage if you corpse drag a little too hard. Its literally been the only current PF content ive done where i never had to put [duty complete] to get a good experience clearing it twice a week. Parties filled super fast at any point in the week.